1. Field of the Invention
The present invention relates generally to the production of slide fasteners, and more particularly to an apparatus for forming a space section devoid of coupling elements in a pair of continuous slide fastener stringers.
2. Prior Art
A number of devices for the purpose described above are known in which a chain of interengaged filamentary coupling elements attached by stitches to a pair of tapes along their adjacent longitudinal edges is cut for a length corresponding to the length of an element-free gap or space section by means of a coacting punch and die. It has been a common practice to this end that the tapes are pulled apart locally in order to allow the punch to enter between the adjacent tape edges so that the cutting of the coupling elements is accomplished without cutting the tapes. However, pulling the tapes locally often makes the tapes to become unrecoverably deformed or otherwise damaged. Further, because of this tape pulling, an increased rate of production with the prior apparatus is difficult to achieve. Such prior art is exemplified by U.S. Pat. No. 3,225,430, issued Dec. 28, 1965, and French Pat. No. 1,561,401, issued Mar. 28, 1969.